The present ubiquitous era needs to be prepared for evolution to the next stage. In the next stage, a unique Internet protocol (IP) address is given to each sensor in a ubiquitous sensor network (USN), and a user can acquire desired information and services from any external network.
Research related to USNs, that is, research related to sensors and sensor networks has been conducted for a long time. A large amount of research in wireless sensor networks (WSNs) has been conducted, not only in South Korea, but also in foreign countries. The ZigBee Alliance is one of the most popular associations of companies in the USN field. ZigBee is the name of a low-power wireless networking standard. The ZigBee standard builds on the IEEE 802.15.4 standard, which specifies the physical layer and the data link layer, and defines the network layer and higher layers. ZigBee has high power efficiency, which would allow, for example, a sensor in a low-power sensor network to last for a few months on two AA-size batteries. In addition, ZigBee may constitute a personal area network (PAN) that has a greater range than Bluetooth. However, a non-IP-based network protocol is used in the network layer, and thus application adaptability is limited.